This proposal requests NCRR funds for the purchase of an integrated computer- controlled isothermal titration calorimeter (ITC) and differential scanning calorimeter (DSC). By providing key thermodynamic insights, these instruments are sought to enhance studies of (a) macromolecular folding and misfolding reactions, (b) enzyme reaction mechanisms, (c) protein-DNA and protein-RNA interactions in gene regulation and RNA processing, and (d) effects of mutations in proteins causing human disease. In each case the proposed instruments will significantly enhance N1H-funded biochemical and structural studies on-going within the CWRU School of Medicine. These studies are of complementary basic and applied importance: deepening fundamental understanding of biochemical processes and elucidating mechanisms of birth defects and disease. The phenomena to be investigated are diverse but share the critical need to correlate structure and mechanism with thermodynamics. ITC and DSC enable thermodynamic parameters to be measured directly, providing the "gold standard" in this field. Such data will complement insights obtained from kinetic and structural approaches using existing shared facilities (stopped-flow spectroscopy, plasmon resonance, NMR spectroscopy and X-ray crystallography). The CWRU School of Medicine is committed to providing the necessary infrastructure under the auspices of the Molecular Biology Core Laboratory and has made provisions for the long-term maintenance of the instruments. There are no instruments currently on the CWRU campus that provide the same capabilities as the proposed TTGDSC calorimeters. This currently imposes a limitation on the research programs of the user group. The requested instruments will therefore significantly enhance the depth and scope of the major users' funded research and will provide general access to state-of-the-art calorimetric analysis to the University community.